In the discussion of the background that follows, reference is made to certain structures and/or methods. However, the following references should not be construed as an admission that these structures and/or methods constitute prior art. Applicant expressly reserves the right to demonstrate that such structures and/or methods do not qualify as prior art.
Known tools comprising replaceable inserts use various means for mounting the inserts to the tool body. Some known inserts are mounted with a locking screw passed through the center of the insert and secured in a taped hole in the insert seating surface. The axis of the taped hole may be perpendicular to the insert and the insert seating surface or the axis of the taped hole may be skewed. However, the density of inserts on the milling tool is limited because of the clearance required when taping the lock screw hole in the insert seating surface, and by the use of wedges and or clamps. In addition, the hole in the insert itself reduces the cross section of the insert, which can reduce insert performance such as strength, in particular for ceramic inserts such as silicon nitride (SiNi) inserts. Some known inserts are mounted with a set screw descending from a side of the insert seating surface. The point of the set screw inserts into and/or contacts, e.g., a depression in the surface of the insert to place the set screw in compression and press the insert against the insert seating surface. However, the chip room for this insert and tool may not be adequate and may foul the tool during operation.
Examples of milling cutters wherein inserts are mounted to the tool body using screws are illustrated in U.S. Pat. No. 4,934,880. Examples of milling cutters wherein inserts are held to the tool body by releasable clamps are illustrated in U.S. Pat. No. 3,588,977. GB 1,209,181 discloses a cutter with an insert secured in a slot by one or more screws.
Inserts for tooling and manufacturing perform under rigorous conditions during operations on iron components. Typically, different irons have different operating conditions and, therefore, different inserts are typically used. Some irons of interest include gray irons, nodular irons, high tensile irons and compacted graphite iron (CGI irons). An insert that may be operationally functional across more than one type iron would be advantageous. Other considerations for inserts include the type of surface provided (rough and finish), ease of indexing of inserts and change-out time of used inserts, secure seating to minimize “fling” of inserts under centrifugal forces, tool life, simple and commonly available accessories, compatibility with existing milling equipment and hardware and securing means that reliably and repeatably place inserts in secure seats.